Unlike so many of his contemporaries, who've held on to their glory days like they're the very lifelines keeping them alive, Robert Plant has managed to stay relevant by digging into a deeper, more varied past. On his Grammy-hogging 2007 collaboration album with Alison Krauss, 'Raising Sand,' he uncovered dusty gems from the Everly Brothers, Gene Clark and Townes Van Zandt. 2010's follow-up, 'Band of Joy,' included songs by Los Lobos, Richard Thompson and Van Zandt again.

By shedding his Golden God image, and Led Zeppelin's mythical standing in the process, Plant has remade himself as a genuine anomaly: an authentic Americana roots artist born and bred in England. While his old cohort Jimmy Page breathes new digital life into Zeppelin's old catalog, Plant is half a world away, figuratively at least, exploring African beats, pan-global rhythms and the many intricacies buried deep in music that has little to do with American blues.

'lullaby and ... The Ceaseless Roar' expands the territorial boundaries of 'Raising Sand' and 'Band of Joy' while working flexibly within their confines. This is a world music album, targeted at the NPR-weaned audience that made 'Sand' a rebirth of sorts for Plant, whose album before that, 2005's 'Mighty ReArranger,' was a somewhat joyless and tentative first dip into these waters. If 'Raising Sand' was a baptism of career-reviving proportions, 'lullaby and ... The Ceaseless Roar' is the grand celebration that follows.

Not that those who've written off Plant as a stuffy, stodgy old man who gave up his rock 'n' roll past for deadly serious grownup music will be swayed to come back around. But now that he's let the dust settle on his Americana recordings, he's globetrotting with a musical thirst of someone a third his age.

From the stripped-down and acoustic sway of 'Little Maggie' (the only song here not written by Plant and members of his band the Sensational Space Shifters, though they did arrange the traditional number) to 'Rainbow''s mix of moody atmosphere and stabbing guitars to the rolling, skittering beats that guide 'Arbaden (Maggie's Babby),' 'lullaby and ... The Ceaseless Roar' finds its inspiration in places as far reaching as the Sahara desert and in the trip-hop scene of '90s Bristol.

Filled with the sounds of banjo, electronic loops and various West African percussion, and little in the way of traditional rock instruments, the 11 songs skim and drift over a landscape of rattling drums, genre- and culture-jumping melodies and an abundance of gray noise. Plant, who produced, gives 'lullaby and ... The Ceaseless Roar' a relentless sense of adventure; Tchad Blake, the mixer who's helped paint records by Elvis Costello, Peter Gabriel and Tom Waits, piles on extra layers of ambiance.

All of which, again, won't convince fans expecting Plant to belt out 'Whole Lotta Love' for the billionth time that the singer is actually now in the most exciting period of his solo career. 'lullaby and ... The Ceaseless Roar' reveals more and more the more and more you listen to it. (Has he ever sounded more mature vocally than he does on the spare ballad 'Stolen Kiss'?) It's a deep, rewarding album, paying back the time and patience you invest. Is it better than any of Led Zeppelin's classic albums? Of course not. But it's probably better than the album they'd make if they were still around.

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